Book contents
- How to Read an EEG
- How to Read an EEG
- Copyright page
- Dedication
- Contents
- Figure Contributions
- Foreword
- Preface
- How to Read This Book
- Part IBasics
- Part IIInterpretation
- Chapter 9Approach to EEG Reading
- Chapter 10Background
- Chapter 11Foreground (How to Describe an Abnormality)
- Chapter 12Common Artifacts
- Chapter 13Normal Variants
- Chapter 14Sporadic Abnormalities
- Chapter 15Repetitive Abnormalities
- Chapter 16Ictal Patterns (Electrographic Seizures)
- Chapter 17Activation Procedures
- Part IIISpecific Conditions
- AppendixHow to Write a Report
- Index
- References
Chapter 15 - Repetitive Abnormalities
from Part II - Interpretation
Published online by Cambridge University Press: 24 June 2021
Book contents
- How to Read an EEG
- How to Read an EEG
- Copyright page
- Dedication
- Contents
- Figure Contributions
- Foreword
- Preface
- How to Read This Book
- Part IBasics
- Part IIInterpretation
- Chapter 9Approach to EEG Reading
- Chapter 10Background
- Chapter 11Foreground (How to Describe an Abnormality)
- Chapter 12Common Artifacts
- Chapter 13Normal Variants
- Chapter 14Sporadic Abnormalities
- Chapter 15Repetitive Abnormalities
- Chapter 16Ictal Patterns (Electrographic Seizures)
- Chapter 17Activation Procedures
- Part IIISpecific Conditions
- AppendixHow to Write a Report
- Index
- References
Summary
Repetitive waveforms may repeat in quick succession (rhythmic) , after nearly regular intervals (periodic), or spike and wave (SW). Periodic discharges are considered markers for neuronal injury. Most forms of repetitive abnormalities are epileptogenic; in specific situations they may also represent ictal patterns. GSW discharges of more than 3 Hz or other evolving discharges of more than 4 Hz are unequivocally ictal patterns, whereas GSW of less than 3 Hz or other evolving discharges of less than 4 Hz lie on an ictal-interictal spectrum. This means that these patterns may or may not be ictal depending on their clinical and electrographic accompaniments. A repetitive pattern is described as a combination of a main term 1 with a main term 2 based on the American Clinical Neurophysiology Society (ACNS) standardized critical care EEG terminology. Main term 1 could be either generalized (G), lateralized (L), bilateral independent (BI), or multifocal (Mf). Main term 2 could be either periodic discharges (PD), rhythmic delta activity (RDA), or generalized spike-wave (GSW). Common rhythmic abnormalities include GRDA and LRDA. Common periodic abnormalities include GPDs, LPDs, and BIPDs.The term “SI” is added to the combination of main terms to denote a stimulus-induced pattern (e.g., SI-GPDs for stimulus-induced GPDs).
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- How to Read an EEG , pp. 134 - 148Publisher: Cambridge University PressPrint publication year: 2021
References
Hirsch, LJ, Fong, MWK, Leitinger, M, et al. American Clinical Neurophysiology Society’s Standardized Critical Care EEG terminology: 2021 version. Journal of Clinical Neurophysiology. 2021 Jan;38(1):1–29.Google Scholar
Pohlmann-Eden, B, Hoch, DB, Cochius, JI, Chiappa, KH. Periodic lateralized epileptiform discharges – a critical review. Journal of Clinical Neurophysiology. 1996 Nov 1;13(6):519–30.Google Scholar
Chong, DJ, Hirsch, LJ. Which EEG patterns warrant treatment in the critically ill? Reviewing the evidence for treatment of periodic epileptiform discharges and related patterns. Journal of Clinical Neurophysiology. 2005 Apr 1;22(2):79–91.Google Scholar
Hirsch, LJ, Claassen, J, Mayer, SA, Emerson, RG. Stimulus‐induced rhythmic, periodic, or ictal discharges (SIRPIDs): a common EEG phenomenon in the critically ill. Epilepsia. 2004 Feb;45(2):109–23.Google Scholar
Accolla, EA, Kaplan, PW, Maeder-Ingvar, M, Jukopila, S, Rossetti, AO. Clinical correlates of frontal intermittent rhythmic delta activity (FIRDA). Clinical Neurophysiology. 2011 Jan 1;122(1):27–31.CrossRefGoogle ScholarPubMed
Moeller, F, Pressler, RM, Cross, JH. Genetic generalized epilepsy. In Oxford Textbook of Clinical Neurophysiology (p. 301). Oxford University Press, Oxford; 2016.Google Scholar
Gaspard, N, Manganas, L, Rampal, N, Petroff, OA, Hirsch, LJ. Similarity of lateralized rhythmic delta activity to periodic lateralized epileptiform discharges in critically ill patients. JAMA Neurology. 2013 Oct 1;70(10):1288–95.Google Scholar
Di Gennaro, G, Quarato, PP, Onorati, P, et al. Localizing significance of temporal intermittent rhythmic delta activity (TIRDA) in drug-resistant focal epilepsy. Clinical Neurophysiology. 2003 Jan 1;114(1):70–8.Google Scholar
Foreman, B, Claassen, J, Khaled, KA, et al. Generalized periodic discharges in the critically ill: a case-control study of 200 patients. Neurology. 2012 Nov 6;79(19):1951–60.Google Scholar
Jadeja, N, Zarnegar, R, Legatt, AD. Clinical outcomes in patients with generalized periodic discharges. Seizure. 2017 Feb 1;45:114–18.Google Scholar
O’Rourke, D, Chen, PM, Gaspard, N, et al. Response rates to anticonvulsant trials in patients with triphasic-wave EEG patterns of uncertain significance. Neurocritical Care. 2016 Apr 1;24(2):233–9.Google Scholar
Boulanger, JM, Deacon, C, Lécuyer, D, Gosselin, S, Reiher, J. Triphasic waves versus nonconvulsive status epilepticus: EEG distinction. Canadian Journal of Neurological Sciences. 2006 Jul;33(2):175–80.Google Scholar
Glauser, T, Shinnar, S, Gloss, D, et al. Evidence-based guideline: treatment of convulsive status epilepticus in children and adults: report of the Guideline Committee of the American Epilepsy Society. Epilepsy Currents. 2016 Jan;16(1):48–61.CrossRefGoogle ScholarPubMed
Punia, V, Garcia, CG, Hantus, S. Incidence of recurrent seizures following hospital discharge in patients with LPDs (PLEDs) and nonconvulsive seizures recorded on continuous EEG in the critical care setting. Epilepsy and Behavior. 2015 Aug 1;49:250–54.Google Scholar
Ruiz, AR, Vlachy, J, Lee, JW, et al. Association of periodic and rhythmic electroencephalographic patterns with seizures in critically ill patients. JAMA Neurology. 2017 Feb 1;74(2):181–8.Google Scholar
Herman, ST, Abend, NS, Bleck, TP, et al. Consensus statement on continuous EEG in critically ill adults and children, part I: indications. Journal of Clinical Neurophysiology. 2015 Apr;32(2):87.CrossRefGoogle ScholarPubMed
Maciel, CB, Gilmore, EJ. Seizures and epileptiform patterns in SAH and their relation to outcomes. Journal of Clinical Neurophysiology. 2016 Jun 1;33(3):183–95.CrossRefGoogle ScholarPubMed
Claassen, J, Jette, N, Chum, F, et al. Electrographic seizures and periodic discharges after intracerebral hemorrhage. Neurology. 2007 Sep 25;69(13):1356–65.Google Scholar
Fitzpatrick, W, Lowry, N. PLEDs: clinical correlates. Canadian Journal of Neurological Sciences. 2007 Nov 1;34(4):443–50.Google Scholar
Struck, AF, Westover, MB, Hall, LT, et al. Metabolic correlates of the ictal-interictal continuum: FDG-PET during continuous EEG. Neurocritical Care. 2016 Jun 1;24(3):324–31.Google Scholar
Li, HT, Wu, T, Lin, WR, et al. Clinical correlation and prognostic implication of periodic EEG patterns: a cohort study. Epilepsy Research. 2017 Mar 1;131:44–50.Google Scholar
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